1. Field of the Invention
The present invention relates to an electrical connector connected to a flexible plane-type conductor cable formed as a flexible thin sheet body which comprises belt-like conductor portions arranged in parallel to each other and a film-like insulation sheath applied thereover. This flexible plane-type conductor cable is hereinafter referred to as an "FPC".
2. Statement of the Prior Art
A conventional electrical connector for an FPC is known in the official gazette of Japanese Patent Publication No. 48833/1982 (examined) or the like. The construction and problems of this known electrical connector will be described with reference to FIGS. 5 to 7 for convenience. FIG. 5 is a perspective view of the known electrical connector, FIG. 6 a cross-sectional view taken along the line VI--VI of FIG. 5, and FIG. 7 a partially enlarged cross sectional view showing a state in which the electrical connector shown in FIG. 5 is in use.
As shown in FIG. 5, the known electrical connector 1 is basically constructed such that crimping pieces 3 of tongue-like sheet are provided on the side edges of a web 2 in such a manner as to erect therefrom and that an arc contact portion 5 comprising an expanded arc 4 substantially normal to the sheet body of the crimping piece 3 is provided on the web 4 at a position adjacent to the joint between the crimping piece 3 and the web 2 in a raised fashion for each crimping piece 3.
As shown in FIGS. 6 and 7, an FPC 6 to which this electrical connector 1 is attached is formed into a flexible sheet body comprising belt-like conductor portions 7 arranged in parallel to each other and securely sealed with a film-like insulation sheath 8. The crimping pieces 3 are caused to penetrate through this FPC 6 at predetermined positions, and the upper half portion of each crimping piece 3 that has penetrated through the FPC 6 is then crimped in a direction indicated by an arrow 31 in FIG. 6, i.e. toward over the arc contact portion 5 so as to form a curled portion 10, which is then brought into press contact with the arc contact portion 5 to thereby securely hold the FPC 6 therebetween. When securely held by means of the curled portion, the insulation sheath 8 of the FPC 6 is partially stripped off by means of the leading-end edge of the crimping piece 3, which allows to the conductor portion 7 and the curled portion 10 of the crimping piece 3 to electrically contact each other. Thus, the electrical connector 1 is securely attached to the FPC 6 for electrical connection.
In the conventional electrical connector 1 constructed as described above, since the arc contact poerion 5 that is laid over the curled portion 10 comprises the expanded arc 4, the external arc 11 of the curled portion 10 and the expanded arc 4 are brought into circumscribed arc relationship via the FPC 6 from a geometrical point of view.
As a result of this, since a dot contact or an approximate dot contact is established between the conductor portion 7 and the circumscribed arcs 4 and 11, it is not possible to have a contact allowing good electricity conducting therebetween at all times. Moreover, if there is even a slight error in the accuracy with which the crimping piece 3 is curl processed, the dot contact between the leading-end edge of the crimping piece 3 which is on the moving side and the FPC 6 which is on the fixed side becomes too much or too little, causing a case in which the FPC 6 is damaged or the insulation sheath 8 is not sufficiently stripped off. However, the control of accuracy with which curl processing is carried out is extremely difficult from a mass-production technology point of view, and there is a drawback that articles having unstable electrical connection with the FPC 6 are produced.